Simulation Analysis On Creep Of Concrete Structures

Now the structure of concrete is in the tendency of complication,which is not only limited to the structure of buildings, such as extra-long concrete structures like long-spanned Bridge and high arch dam, but also limited to actual complicated stress which would cause deformation and crack problems. Under sustained load, concrete structure will be evidently in creep deformation, threatening overall security and stability of the structure. Considering the extra-long concrete structure, how to solve the crack problem caused by expansion joint absent without affecting the aesthetics and usage of a building has become the hot pot of scholar researching. In this paper, the combination of experiment and simulation are used respectively in analyzing the structure of concrete column and the creep of extra-long concrete structure beam.Two main lines are studied in this paper: 1. Experiment. Concrete beam adopted as the research object, which are used to simulate as flexural member, are analyzed focusing on creep from the aspects of concrete strength grade, expansive agent dosage, reinforcement ratio and the load stress, and the potential influences of these four factors on the specimen will be concluded to adjust the combination of structure material to lower the cracking possibility cased by creep. 2. Simulation.Firstly, the influences of strength grade and first rate of concrete to the creep of concrete short column will be simulated by using ANSYS finite element; secondly factors affecting the experiment will be compared in simulating the creep of extra-long concrete beam; finally, the two of the following conclusions will be get after contrasting the results by combining with the features of experiment and the advantages of software.(1) Under sustained load, structure column creep deformation is quick at the early period then turns to stable state; concrete column with high strength grade is greater in compressive strength and its creep deformation is relatively low; with the influence of creep effect, stirrup stress is in the tendency of reduce with time; stirrup has constraint function on concrete columns with, that means the greater reinforcement stirrup is, the lighter the creep deformation is, which signifies that the compressive strength and bearing capacity of the concrete columns can be improved. Therefore, within the budget, choosing high strength concrete and enhancing reinforcement ratio can reduce the possibility of cracking caused by concrete structure column deformation.(2) Under sustained load, super-long concrete structure beam total creep deformation curve, compensation creep deformation curve and basic creep deformation curve are roughly the same; the deformation of concrete structure changes in fast speed at the early stage, and it turns to slow after a period of time and stays steady at the last until the end of the survival of concrete structures; the complementary creep deformation value of concrete structure beam (that is the concrete beam caused by its own factors such as the gravity of creep deformation value) is less than the total creep deformation value; reinforced concrete along with variable deformation value is less than the creep deformation of a plain concrete beam; the higher the concrete strength is, the smaller the creep of concrete structure beam deformation value is. Therefor, within the limitation of economic cost, the high-strength can be the best choice for super-long concrete structure; the full use of reinforcement can effectively reduce the creep deformation; the use of shrinkage compensating concrete materials can achieve the seamless structure design; the influence of stress loading on creep deformation can not be ignored, especially the heavier effect on concrete members which has large difference in structure section stress.